A. Summary of the Invention
The present invention relates generally to marine seismic streamers of the type including multiple serially connected streamer sections and more particularly, to a coupler for connecting together adjacent pairs of such streamer sections.
B. Description of the Prior Art
Heretofore, a number of marine seismic streamers have been developed for making seismic surveys of the earth formations underlying bodies of water. In general, such marine seismic streamers include a lead-in cable and a plurality of serially connected sections formed of oil flled plastic tubes surrounding stress members, and various instruments, such as hydrophones, and associated electrical equipment, such as wires and transformers. Examples of such streamers are disclosed in U.S. Pat. Nos. 2,465,696, and U.S. Pat. No. 3,371,739. Such marine seismic streamers are often as long as two miles and are made up of multiple streamer sections, each having a length of up to about 300 feet.
Various coupler devices have been developed to connect together adjacent seismic streamer sections. Such couplers must provide a high strength mechanical connection to transmit tension and torque between the stress members of the adjacent streamer sections and a reliable substantially water proof electrical connection between the electrical conductors of adjacent sections. Advantageously, a coupler should be compact and relatively light in weight. Additionally, a coupler should present a clean streamlined external profile so as to reduce turbulence as the streamer is towed through the water. Moreover, a coupler should be easy to connect and disconnect. Examples of streamer couplers are disclosed in U.S. Pat. Nos. 3,376,948, 3,812,455, 4,260,211, and U.S. patent application Ser. No. 295,499, filed Aug. 24, 1981.
In the coupler of U.S. Pat. No. 4,260,211, tension forces are transmitted across the coupler by a quick connect sleeve. The quick connect sleeve defines a cavity in which electrical connection is established by means of a floating connector. Establishing the electrical connection with the floating connector is often time consuming.
The coupler of U.S. Pat. No. 3,812,455, includes mating semicylindrical portions with male and female electrical plugs mounted along the diametrical planes thereof. The semi-cylindrical portions are mechanically connected together by means of bolts. The tension forces are carried by the semi-cylindrical portions and the bolts. Thus, the semi-cylindrical portions must be high strength, relatively heavy structures. The coupler of U.S. patent application Ser. No. 295,499, filed Aug. 24, 1981, likewise includes mating semi-cylindrical portions that are held together by locking rings. The semi-cylindrical portions include interfitting alternating teeth, which transmit tensile forces across the coupler.
The coupler of U.S. patent application Ser. No. 295,499 is lighter than that of U.S. Pat. No. 3,812,455; however, it is necessarily high strength and of relatively heavy construction. The electrical plugs in the coupler of U.S. patent application Ser. No. 295,499 are supported in floating relation relative to the coupler body so that deformation of the coupler body is not transmitted to the plugs. The floating arrangement of the plugs occasionally makes it difficult to assemble the coupler. Additionally, both the couplers of U.S. Pat. No. 3,812,455, and U.S. patent application Ser. No. 295,499, require elaborate sealing arrangements to preserve their watertight integrity.
It is an object of the present invention to provide an improved seismic streamer coupler that overcomes the shortcomings of the prior art. More specifically, it is an object of the present invention to provide a high strength, light weight seismic streamer couple that may be readily coupled and uncoupled in the field.